Electrical junction boxes that are installed in vehicles are provided with a waterproofing structure so as to prevent water from intruding into the electrical junction boxes during driving in the rain or during washing of the vehicles. In an electrical junction box disclosed in JP 2014-27723A, a body case and an upper cover attached to the body case each have a double-wall structure, and an outer wall of the body case is inserted between outer and inner walls of the upper cover. A leading end of the outer wall of the upper cover and an upper end of the outer wall of the body case have stepped shapes that come into contact with each other. Water intruding into the body case through a gap at a seam between the outer wall of the upper cover and the outer wall of the body case is discharged from a drain outlet in a lower cover.
Incidentally, according to JP 2014-27723A, although intrusion of water into the body case is made difficult by the leading end of the outer wall of the upper cover and the upper end of the outer wall of the body case having the stepped shapes, the gap is formed at the seam between the outer wall of the upper cover and the outer wall of the body case, and therefore, there is a possibility that water intruding from the gap at the seam may pass between the stepped shapes and thus intrude into the body case. According to JP 2014-27723A, a drainage structure is provided by the body case having a double wall, and water intruding into the body case is discharged through the drainage structure. However, there is a problem in that, as a result of having such a double-wall drainage structure, the configuration is complex.
The present invention was made based on circumstances such as those described above, and it is an object thereof to provide an electrical junction box with which intrusion of water into a case can be suppressed with a simple configuration.